Product Pricing

Product pricing adapters calculate prices when products are queried or added to cart. Use them to implement taxes, discounts, rounding, and currency conversion.

For conceptual overview, see Pricing System.

Creating an Adapter

Extend ProductPricingAdapter and register it with ProductPricingDirector:

import {
  ProductPricingAdapter,
  ProductPricingDirector,
} from '@unchainedshop/core-pricing';

class MyProductPricing extends ProductPricingAdapter {
  static key = 'my-shop.pricing.custom';
  static version = '1.0.0';
  static label = 'Custom Product Pricing';
  static orderIndex = 0;

  static isActivatedFor({ product, currencyCode }) {
    return true; // Activate for all products
  }

  async calculate() {
    const { product, quantity, currencyCode } = this.context;

    this.result.addItem({
      amount: 1000, // 10.00 in cents
      isTaxable: true,
      isNetPrice: true,
      category: 'BASE',
      meta: { adapter: this.constructor.key },
    });

    return super.calculate();
  }
}

ProductPricingDirector.registerAdapter(MyProductPricing);

Examples

Tax Calculation

class SwissTaxAdapter extends ProductPricingAdapter {
  static key = 'my-shop.pricing.swiss-tax';
  static orderIndex = 20; // After base price and discounts

  static isActivatedFor({ country }) {
    return country === 'CH';
  }

  async calculate() {
    const taxRate = 0.081; // 8.1% Swiss VAT
    const taxableAmount = this.calculation.sum({ isTaxable: true });

    if (taxableAmount > 0) {
      this.result.addItem({
        amount: Math.round(taxableAmount * taxRate),
        isTaxable: false,
        isNetPrice: false,
        category: 'TAX',
        meta: { rate: taxRate, adapter: this.constructor.key },
      });
    }

    return super.calculate();
  }
}

Bulk Discount

class BulkDiscountAdapter extends ProductPricingAdapter {
  static key = 'my-shop.pricing.bulk-discount';
  static orderIndex = 10; // After base price, before tax

  async calculate() {
    const { quantity } = this.context;

    if (quantity >= 10) {
      const baseTotal = this.calculation.sum({ category: 'BASE' });
      const discountRate = 0.1; // 10% off

      this.result.addItem({
        amount: -Math.round(baseTotal * discountRate),
        isTaxable: true,
        isNetPrice: true,
        category: 'DISCOUNT',
        meta: { type: 'bulk', rate: discountRate },
      });
    }

    return super.calculate();
  }
}

Price Rounding

class PriceRoundingAdapter extends ProductPricingAdapter {
  static key = 'my-shop.pricing.rounding';
  static orderIndex = 30; // Run last

  async calculate() {
    const { calculation = [] } = this;

    if (calculation.length) {
      const [basePrice] = calculation;
      const rounded = this.roundToNext(basePrice.amount, 50);

      this.resetCalculation();
      this.result.addItem({
        amount: rounded,
        isTaxable: basePrice.isTaxable,
        isNetPrice: basePrice.isNetPrice,
        meta: { adapter: this.constructor.key },
      });
    }

    return super.calculate();
  }

  roundToNext(value: number, precision: number) {
    const remainder = value % precision;
    return remainder === 0 ? value : value + (precision - remainder);
  }
}

Currency Conversion

class CurrencyConversionAdapter extends ProductPricingAdapter {
  static key = 'my-shop.pricing.currency';
  static orderIndex = 1;

  async calculate() {
    const { currencyCode, baseCurrencyCode } = this.context;

    if (currencyCode !== baseCurrencyCode) {
      const rate = await this.getExchangeRate(baseCurrencyCode, currencyCode);

      for (const item of this.calculation) {
        item.amount = Math.round(item.amount * rate);
      }
    }

    return super.calculate();
  }

  async getExchangeRate(from: string, to: string) {
    // Fetch from your exchange rate service
    return 1.1;
  }
}

Adapter Properties

Property	Type	Description
key	string	Unique identifier
version	string	Version for tracking
label	string	Human-readable name
orderIndex	number	Execution order (lower = earlier)

Context Properties

Available in this.context:

Property	Description
product	The product being priced
quantity	Quantity requested
currencyCode	Target currency
country	Country code

Related

• Pricing System - Conceptual overview
• Delivery Pricing - Shipping fees
• Payment Pricing - Payment fees
• Order Discounts - Order-level discounts